1. Field of Invention
The invention relates to a sewing method for forming stitches, such as embroideries, on a work cloth, and to a patterned cloth formed using the method above.
2. Description of Related Art
Conventionally, a sewing apparatus, such as a sewing machine, performs sewing on a work cloth using upper and lower threads in cooperation with a thread take-up, a thread loop taker and a needle. The needle is threaded with the upper thread and moves vertically. A general home sewing machine performs sewing using a single needle attached to a lower end of a needle rod. Accordingly, when the upper thread wound around a spool runs out or when an upper thread needs to be changed to sew a different color of a color pattern, after the spool for the upper thread is changed, the upper thread is threaded to a predetermined guide portion provided on the sewing machine and then needs to be threaded through a needle hole.
In the known sewing apparatus, the sewing needle has the needle hole at its lower end and a thread is threaded through the needle hole. Therefore, it is difficult to form a pattern unless the needle cooperates with a thread take-up and a thread loop taker during a sewing operation. That is, a driving mechanism that drives the thread take-up and the thread loop taker is needed.
A known sewing apparatus used with a sewing cartridge accommodating a needle and a spool therein, that can be attached to and detached from the sewing apparatus, wherein threading of an upper thread and threading of an upper thread through a needle hole can be omitted when an upper thread wound around a spool runs out or when an upper thread needs to be changed to sew a color pattern, is disclosed in U.S. Pat. No. 4,100,867, the disclosure of which is incorporated herein by reference.
In the sewing apparatus disclosed in U.S. Pat. No. 4,100,867, the needle attached to the sewing cartridge is similar to a general sewing needle wherein a thread is threaded through a needle hole at its lower end. When the sewing cartridge is attached to the sewing apparatus, the needle and a needle up and down mechanism, provided to the sewing apparatus, are connected to each other to move integrally. As a machine motor is driven, the needle is moved up and down by the needle up and down driving mechanism with respect to the sewing cartridge fixed to the main body of the sewing machine. Thus, the operation in which the needle passes through a work cloth is repeated, whereby sewing is performed on a work cloth using upper thread and a looper member.
Japanese Laid-Open Patent publication No. 7-24173 discloses a sewing cartridge that can be easily detachably attached to a sewing machine. In a state where the sewing cartridge is removed from the sewing machine, an upper thread is held by a cartridge lever at a position, which is out of an operating range of end portions of a thread take-up and is higher than a highest thread take-up position. When the sewing cartridge is attached to the sewing machine, the end portions of the thread take-up are inserted into respective openings provided under the cartridge lever and a needle clamp in the sewing cartridge and a cartridge support shaft are connected each other. In this state, when a main shaft is rotated, the needle clamp and the end portions of the thread take-up move downward, so that the upper thread is pulled. Then, the cartridge lever is rotated downward, against an urging force from a spring, by a tension produced on the upper thread. After that, the needle clamp ascends, and a work cloth is advanced. As the end portions of the thread take-up move upward, the cartridge lever is pushed upward by the end portions of the thread take-up. The disclosure of Japanese Laid-Open Patent publication No. 7-24173 is herein incorporated by reference.
U.S. Pat. No. 3,749,039 discloses a sewing cartridge including a casing, a housing area formed in the casing to house a spool therein, a thread tension applying mechanism, and a plurality of thread guide portions. When the sewing cartridge is attached to a sewing apparatus, an upper thread, extending from the spool, in the sewing cartridge is automatically threaded onto a thread tensioning member provided in the sewing apparatus. The disclosure of U.S. Pat. No. 3,749,039 is herein incorporated by reference.
In the sewing cartridge disclosed in Japanese Laid-Open Patent No. 7-24173, the needle clamp and the cartridge lever need to be moved up and down. Therefore, the sewing cartridge becomes large because the sewing cartridge needs to be large enough for the needle clamp and the cartridge lever to move vertically therein. In addition to this, a number of parts required to be installed in the sewing cartridge is increased and an internal structure of the sewing cartridge becomes complicated. The sewing cartridge disclosed in U.S. Pat. No. 3,749,039 is provided with the housing area for the spool, the thread tension applying mechanism and the plurality of thread guide portions, so that the sewing cartridge also becomes large in size. Further, a number of parts required to be installed in the sewing cartridge is increased and an internal structure of the sewing cartridge becomes complicated.
The invention provides a sewing method that offers excellent stitches and provides a patterned cloth using the sewing method.
According to one aspect of the invention, a sewing operation is performed on a workpiece that moves along an X-Y plane perpendicular to an axial direction of a hollow needle. The hollow needle has an inclined opening that is formed by angularly cutting a portion of an end of the hollow needle that penetrates the workpiece with respect to the axial direction of the hollow needle. The sewing operation is performed by reciprocating the hollow needle in a penetrating direction, using a thread threaded in the hollow needle. The sewing operation includes forming a plurality of stitches in a first stitching direction, and forming a plurality of stitches in a second stitching direction opposite to the first stitching direction, following and in parallel with the plurality of stitches formed in the first stitching direction, by turning the hollow needle around in a direction opposite to the needle tip opening direction.